Three related bugs caused oneshot containers to run indefinitely:
1. watcher.go: switch b.policy had no case OneShot, so even when the
idle timeout fired, no remove action was emitted.
2. watcher.go + manager.go/recoverBoxes: idleTimeoutD was only set for
Session and LongRunning on recovery; OneShot defaulted to 0, which
caused the watcher to hit the `timeout <= 0` early-return and skip
all checks entirely.
3. agent/sandbox/v2/options.go: same gap — opts.IdleTimeout == 0 guard
only filled defaults for Session and LongRunning.
Fix: add DefaultOneShotIdleTimeout (30 min), wire it in recoverBoxes
and options.go, and add case OneShot → Remove in watcher.go.
Made-with: Cursor
c26d764857